You can have your fruitcake and eat it too – and still look fabulous in your little black dress! Here’s how...

What's one more cookie, right?

For many of us, that’s the guiding principle of the holiday season – the six-week gorge-fest that starts with Thanksgiving dinner and continues through office holiday parties, Hanukkah celebrations, Christmas dinner and New Year's Eve cocktails.

'Tis the season of socializing, scarfing, stressing and – if you’re not careful – blimping out like Santa Claus.

“The holidays are really only three or four days, and if you blow it on just those days, you can usually recover from the damage,” says registered dietician Kathy Taylor, M.S., R.D., director of nutrition at Grady Memorial Hospital in Atlanta, Ga.

“But it's the mentality that you can let everything go during two or three months that causes weight gain,” she says.

A 2010 University of Oklahoma study found that the average college student gained more than a pound during Thanksgiving break. But those who were overweight or obese gained twice as much.

Another University of Oklahoma study, which covered the Thanksgiving-through-New Year’s period, found an average gain of 1.75 pounds of body fat.

A pound or two may seem like no big deal, but among overweight people, weight gained during the holidays stays all year, according to a year-longNational Institutes of Health study.

But don’t just shrug your shoulders and grab another glass of eggnog: With planning and vigilance, you can stay slim without sacrificing fun. Here’s how.

1. Slim down recipes. Not every holiday dish requires two sticks of butter or three cups of sugar. Instead of smothering yams with syrup and marshmallows, use apple cider vinegar, along with carrots, raisins, cinnamon and ginger.

“It’s still a sweet dish, but you actually get to taste the yams,” says Naomi Kakiuchi, R.D., a Seattle nutritionist and culinary educator.

A list helps curb browsing and impulse purchases. You can go old-school, with a pen and paper, or use technology such as Kitchen Monki, which can deliver grocery lists directly to your cell phone based on recipes you’ve chosen.

Instead of squandering calories on heat-'n'-eat rolls and mashed potatoes, go for once-a-year treats like your Aunt Sophie’s famous stuffing. If a gingerbread cookie is less scrumptious than it looked, toss it after the first bite.

Ratchet down holiday stress by taking time to relax, whether it’s watching a guilty-pleasure TV show or listening to music. Exercise is a proven stress-reducer, so squeeze in 10-minute walks twice daily.

Money worries are the last thing you need during the holidays, so don’t succumb to pressure to overspend and probe the universe for the perfect gift for each of your 12 cousins. Instead, have your family draw names so each person buys and receives one gift.

Or make holiday decorations with your kids.

“Kids feel super when they see that star they made on top of the tree,” Cora says.

5. Get your zzz’s. Most adults need at least seven hours of sleep. But shut-eye may get short shrift when you’re braving malls, baking 40 batches of cookies and shuttling relatives to the airport at all hours.

Sleep deprivation, however, can lead to weight gain by increasing levels of an appetite-stimulating hormone called ghrelin, while decreasing levels of leptin, a hormone that makes you feel full.

“Also, skimping on sleep leads to a lot of coffee drinking, which keeps people on edge and awake, and you end up with a vicious cycle,” Cora says.

6. Avoid temptation. Don't fill your house with bowls of M&M’s or hang candy canes on your Christmas tree. As soon as you finish baking, put your goodies in the freezer or wrap them for gifts. At a party, park yourself away from candy bowls and buffet tables.

“The more hassle it is to eat, the less we eat,” says Brian Wansink, Ph.D., author of Mindless Eating (Bantam) and director of the Cornell Food and Brand Lab at Cornell University in Ithaca, N.Y.

In one of Wansink’s studies, secretaries ate more than twice as many Hershey’s Kisses when the candies were placed in a clear bowl on their desks than when they were placed six feet away.

7. Don’t arrive at parties hungry. “People say, ‘I’m going to save my calories for the party,’ and then they get to the event ravenous and binge,” notes nutritionist Kathy Taylor of Auburn University.

Eat breakfast, lunch and dinner throughout the holiday season, and choose snacks that aren’t full of empty carbs. Some healthy options: a handful of nuts, celery and peanut butter, or a low-fat granola bar.

8. Chew sugar-free gum while you bake. You’ll be less likely to sample as you mix and stir, says New York City fitness trainer and weight-loss coach Jay Cardiello.

Don’t bake while you’re hungry, either. And taste the batter only once when you’re scraping the bowl, then fill it immediately with soapy water.

Alcohol, which flows plentifully this time of year, is another weight-gain temptation: It impairs judgment and weakens your resolve for sensible eating. So besides guzzling unwanted calories, you may end up with your hand in the cookie jar all night. An 8-ounce cup of spiked eggnog has 370 calories; a 1.5-ounce glass of 53-proof Kahlua has 170 calories.

“After one drink, move on to low- or no-calorie beverages such as sparkling water,” Kakuichi says.

10. Sit next to your most gregarious relatives. “You'll be so busy talking that you’ll eat at a slower pace and consume less,” says Mark Blegen, Ph.D., associate professor of exercise and sport science at St. Catherine University in St. Paul-Minneapolis.

11. Wear a pedometer. It may not be the ultimate fashion accessory, but it’s a good weight-loss tool. Research shows that counting steps leads to taking more of them. Aim for 10,000 daily.

“For experienced walkers I advise increasing the daily level to 15,000-20,000 steps to compensate for the extra holiday eating and drinking,” she says.

Though you may be too busy for a full trip to the gym, the holidays provide ample opportunities to boost step mileage, such as shopping, dancing at parties, delivering meals, taking walks to enjoy holiday decorations, and taking a stroll during an airport layover, Napolitano says.

Here’s more motivation: It takes 1,540 steps to burn off one serving of mashed potatoes and 2,520 steps to burn off a chocolate-chip cookie, according to GlobalFit research.

12. Weigh yourself daily. Stepping on the scale daily is a method recommended by researchers at the National Weight Control Registry, a long-term study of successful dieters. It’s especially helpful during high-risk periods such as the holidays.

Besides, a daily check-in ensures that you won’t wake up on Jan. 1, shocked that you’ve gained 10 pounds.

Not only is serotonin a mood booster, but it’s also one of the brain chemicals responsible for feeling full. Even artificial light, especially in the morning, can help suppress food cravings and overeating, Rosenthal says.

14. Bring nutritious fare to potlucks. You’ll be guaranteed healthy eats and have no excuse for bingeing on frosted brownies.

Though raw veggies will probably sit untouched, a roasted vegetable platter is always a hit. Cut big wedges of carrots, zucchini, mushrooms and parsnips; toss with herbs; and roast for 15-25 minutes at 350 degrees.

15. Wear form-fitting clothing. “Leave the Christmas sweater in the closet,” Blegen says. “The baggier our clothes, the more we will eat.”

Besides, feeling your belly press against your jeans is a good reminder to go easy on pecan pie.

16. Savor the season. Eating, drinking and partying aren’t the only ways to have holiday fun. Organize family activities and create new traditions, such as snowshoeing or a walking tour of your neighborhood’s holiday-lights displays.

“The season is about spending quality time with the people you love and enjoying traditions,” Cora says.

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